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Taizhou Hongjia Valve Co.,Ltd
Add : Ganjiang Industrial Area,Yuhuan,Zhejiang, China
E-mail : hongjia@hongjiavalve.com
Tel : 86-576-87453778
Fax : 86-576-87453939
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NEWS CENTER
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What kind of packing is good for cryogenic valves?
There are many types of sealing packing used in valves, such as rubber packing, metal packing, V-shaped packing, O-ring, etc., and other carbon fiber packing, ceramic fiber packing, etc. are very suitable for high temperature valves. In the product. So, what kind of packing is good for cryogenic valves? We know that low-temperature valves are mainly used in low-temperature environments. Therefore, their sealing packing must have low-temperature resistance. The more commonly used are paraffin asbestos packing and flexible graphite packing. At present, these two kinds of packing are used in low-temperature valves. It is better, the specific introduction is as follows: 1. Paraffin asbestos filler is made of asbestos fiber impregnated with paraffin wax, used for low temperature and cryogenic valves. This kind of sealing packing has the characteristics of good resistance to weak acid and strong alkali, high strength and good adsorption performance. 2. The temperature resistance of flexible graphite filler is very good. It can not only be applied to -200℃, but also can be used up to 500℃ in high-temperature oxidizing medium, and can be applied to 2000℃ in non-oxidizing medium, and can maintain excellent performance. The tightness. In addition, the flexible graphite packing has unique flexibility and resilience. The cut packing can be freely bent over 90° in the axial direction. During use, it will not leak due to temperature and pressure changes, vibration and other factors, so it is safe and reliable, and is an ideal seal. Material. Of course, in addition, flexible graphite filler also has the characteristics of strong corrosion resistance, low friction coefficient, good self-lubricity, low friction coefficient, good self-lubricity, and long service life.
2021-11-05
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News
Causes and solutions for the spool of cryogenic valve falling off
For cryogenic valves used in some special environments, over time, their switches will often show corrosion and wear. Once this happens, it will inevitably lead to failure of the connection between the valve stem and the valve core, thereby making the cryogenic valve valve The core is falling off. Of course, human factors cannot be ignored. For example, improper operation can also cause this phenomenon. After this happens, the next series of problems will follow. For example, the cryogenic valve cannot be opened after it is closed, and it can only be cut out from the system and replaced; and if it cannot be cut out from the system, there will only be another Process or device shutdown processing. When the valve core of the cryogenic valve falls off and cannot be cut out, how should we deal with it? This is a problem that we urgently need to solve. The following is a solution compiled by Bangwei Valve Factory for your reference. 1. Under the condition that the medium is sealed, do not move the valve body, valve core and valve seat, and change the assembly method of the valve cover, valve stem, copper sleeve, packing and gland; 2. After the above changes, the valve core is exposed, and then the valve stem and the valve core are restored by conventional methods, so that the three parts of the valve can be continuously sealed and the valve can be reopened. 3. After the bonnet of the cryogenic valve is disassembled, except for special valves, the wedge angle of the valve core is within the friction angle region. No matter how the pressure on the two ends of the valve core changes, the valve core will not squeeze from the valve seat under self-locking conditions. Come out, for the flat valve core, there is no squeeze out.
2021-11-05
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News
What are the uses of pneumatic cryogenic gate valves?
The pneumatic low-temperature gate valve is made of stainless steel and has the characteristics of stainless steel, that is, high hardness, high wear resistance, high temperature resistance, strong corrosion resistance, etc. So, what are the uses of such a powerful pneumatic cryogenic gate valve? Next, I will give you a specific introduction. Pneumatic cryogenic gate valves are widely used in petroleum, chemical, mining, electric power, papermaking, pharmaceutical, food, municipal, urban construction, water supply and drainage, mechanical equipment supporting and electronic industries. It is a control component in the pipeline fluid conveying system. Its main function is to change the section of the pipeline passage and the flow direction of the medium. It has various functions such as adjustment, check, stop, diversion, throttling, and diversion. Pneumatic cryogenic gate valve can be used in various types of fluid pipelines such as water, gas, steam, oil, mud, liquid metal, various corrosive media, and radioactive fluid. Its working pressure can be from 0.0013MPa to 1000MPa. high pressure.
2021-11-05
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News
Development and optimization of electric high temperature gate valve
The relevant content of the low temperature gate valve has been introduced for everyone in a lot of space. Today we will talk about another kind of gate valve, the electric high temperature gate valve. The electric high temperature gate valve is a gate valve with a single-sided metal hard seal cut-off type high temperature resistant gate valve. Mainly used in the flue gas turbine inlet pipeline of a catalytic cracking unit. It is fully opened during normal operation and quickly closed when it fails. It is a key valve for automatic interlocking of flue gas shutoff and emergency shutdown. Under normal circumstances, the number of actions is less. In the 1990s, China began to pay attention to the design of electric high-temperature gate valves. Among the commonly used structures, the valve body and the bonnet adopt riveted welding structure, and the sealing form adopts a wedge-type double gate seal structure or a single-sided hard seal with a steam-assisted seal. However, due to lack of computer-aided design capabilities at that time, the structure was not optimized. Especially for the plate reinforcement, after a certain number of years of use, weld cracks will occur, which seriously affects normal production and is prone to safety hazards. Therefore, some technicians use AnsysWorkbench thermal-structure coupling analysis method to analyze the thermal characteristics of the electric high-temperature gate valve body, determine the strain and stress distribution at the ribs, and use the parameter optimization module of Workbench to optimize the design of the ribs based on the calculation results. , Which makes the service life of the electric high temperature gate valve longer.
2021-11-05
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News
Introduction of commonly used cryogenic valves
1. Low temperature gate valve The standard cryogenic gate valve is one-way sealed, and its elastic gate has a 3mm relief hole, which connects the valve cavity with the upstream pipeline. When the valve cavity is abnormally increased in pressure, the pressure balance can be achieved through the relief hole and the upstream pipeline. Inside the valve, the upstream medium pressure presses the elastic gate against the downstream valve seat sealing ring to achieve downstream low-pressure side sealing. The two-way sealed gate valve is to set a pressure reducing valve outside the valve cavity without having to open a hole on the gate. External pressure relief enables the gate valve to achieve upstream and downstream two-way sealing. The ultra-low temperature gate valve must mark the flow direction of the medium on the valve body. 2. Cryogenic ball valve The ultra-low temperature ball valve adopts a top-mounted structure. The soft-seal ball valve is cheap and has a low leakage rate. It is only used for small-caliber and low-pressure working conditions. In contrast, hard-sealed ball valves are expensive and have a high leakage rate, but they can be used for fluids containing solid particles and have good erosion and abrasion resistance. LNG soft-seal valve seat can withstand -196℃ PCTFE (KEL-F). The soft-seal ball valve is limited to small-caliber and low-pressure working conditions. The large-caliber high-pressure ball valve should use a metal-to-metal hard seal structure. Butt-welded valves used in low temperature working conditions implement the special grade requirements specified by ANSIB16.34. The ultra-low temperature ball valve must mark the flow direction of the medium on the valve body. 3. Cryogenic butterfly valve Ultra-low temperature butterfly valves require two-way sealing. Most LNG butterfly valves use butt welding end faces. Butt welding butterfly valve has high connection strength (its bearing load is at least twice that of flanged valve), more reliable connection (reduce potential flange leakage), and convenient maintenance (especially the valve seat and butterfly plate of large-diameter butterfly valve) And the valve stem can be replaced online), and the maintenance workload is small and the time is short. The ultra-low temperature butterfly valve must mark the flow direction on the valve body. Based on the influence of the low temperature medium on the sealing performance, the butterfly valve should adopt a double eccentric or triple eccentric structure to reduce or eliminate the phenomenon of excessive squeezing or scratching of the sealing surface during the opening and closing process of the butterfly valve, reducing wear and improving service life. KSB valve seat seal adopts LipSeal structure to achieve good sealing effect. The valve stem seal adopts low-emission composite packing, which can make the packing seal meet the TA-Luft standard.
2021-11-05
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News
Briefly talk about the development of several major valve markets
1. Energy Industry For a long time, the energy industry's demand for valves has maintained a solid and stable growth rate. The total power generation of thermal and nuclear power plants built around the world is 2679030MW, the power generation of the United States is 743391MW, and the power generation of new power plants in other countries in the world is 780,000MW, which will increase by 40% in the next few years. Europe, South America, Asia, especially China's energy market will become a new growth point for the valve market. 2. Chemical industry The chemical industry ranks first in the industry with an output value of more than 1.5 trillion US dollars, and it is also one of the largest demand markets for valves. The chemical industry mostly needs industrial valves with mature designs, high processing quality and rare materials. 3. Oil and gas industry In North America and some developed countries, there are many proposed and expanded petroleum projects. In addition, because people are paying more and more attention to environmental protection, the country has established environmental protection laws and regulations. During the year, the funds invested in oil development and refining will continue to grow. The construction of China's oil and gas long-distance pipelines and the future construction of Russia's long-distance pipelines will directly promote the growth of the oil industry valve market.
2021-11-05